116 lines
5.1 KiB
C
Executable file
116 lines
5.1 KiB
C
Executable file
/* (C) 2001-2008 Timothy B. Terriberry
|
|
(C) 2008 Jean-Marc Valin */
|
|
/*
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions
|
|
are met:
|
|
|
|
- Redistributions of source code must retain the above copyright
|
|
notice, this list of conditions and the following disclaimer.
|
|
|
|
- Redistributions in binary form must reproduce the above copyright
|
|
notice, this list of conditions and the following disclaimer in the
|
|
documentation and/or other materials provided with the distribution.
|
|
|
|
- Neither the name of the Xiph.org Foundation nor the names of its
|
|
contributors may be used to endorse or promote products derived from
|
|
this software without specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
|
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
|
|
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
|
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
|
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
|
|
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
|
|
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
|
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
|
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#if !defined(_entenc_H)
|
|
# define _entenc_H (1)
|
|
# include <stddef.h>
|
|
# include "entcode.h"
|
|
|
|
|
|
|
|
typedef struct ec_enc ec_enc;
|
|
|
|
|
|
|
|
/*The entropy encoder.*/
|
|
struct ec_enc{
|
|
/*Buffered output.*/
|
|
ec_byte_buffer *buf;
|
|
/*A buffered output symbol, awaiting carry propagation.*/
|
|
int rem;
|
|
/*Number of extra carry propagating symbols.*/
|
|
size_t ext;
|
|
/*The number of values in the current range.*/
|
|
ec_uint32 rng;
|
|
/*The low end of the current range (inclusive).*/
|
|
ec_uint32 low;
|
|
};
|
|
|
|
|
|
/*Initializes the encoder.
|
|
_buf: The buffer to store output bytes in.
|
|
This must have already been initialized for writing and reset.*/
|
|
void ec_enc_init(ec_enc *_this,ec_byte_buffer *_buf);
|
|
/*Encodes a symbol given its frequency information.
|
|
The frequency information must be discernable by the decoder, assuming it
|
|
has read only the previous symbols from the stream.
|
|
It is allowable to change the frequency information, or even the entire
|
|
source alphabet, so long as the decoder can tell from the context of the
|
|
previously encoded information that it is supposed to do so as well.
|
|
_fl: The cumulative frequency of all symbols that come before the one to be
|
|
encoded.
|
|
_fh: The cumulative frequency of all symbols up to and including the one to
|
|
be encoded.
|
|
Together with _fl, this defines the range [_fl,_fh) in which the
|
|
decoded value will fall.
|
|
_ft: The sum of the frequencies of all the symbols*/
|
|
void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft);
|
|
void ec_encode_bin(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned bits);
|
|
/*Encodes a sequence of raw bits in the stream.
|
|
_fl: The bits to encode.
|
|
_ftb: The number of bits to encode.
|
|
This must be at least one, and no more than 32.*/
|
|
void ec_enc_bits(ec_enc *_this,ec_uint32 _fl,int _ftb);
|
|
/*Encodes a sequence of raw bits in the stream.
|
|
_fl: The bits to encode.
|
|
_ftb: The number of bits to encode.
|
|
This must be at least one, and no more than 64.*/
|
|
void ec_enc_bits64(ec_enc *_this,ec_uint64 _fl,int _ftb);
|
|
/*Encodes a raw unsigned integer in the stream.
|
|
_fl: The integer to encode.
|
|
_ft: The number of integers that can be encoded (one more than the max).
|
|
This must be at least one, and no more than 2**32-1.*/
|
|
void ec_enc_uint(ec_enc *_this,ec_uint32 _fl,ec_uint32 _ft);
|
|
/*Encodes a raw unsigned integer in the stream.
|
|
_fl: The integer to encode.
|
|
_ft: The number of integers that can be encoded (one more than the max).
|
|
This must be at least one, and no more than 2**64-1.*/
|
|
void ec_enc_uint64(ec_enc *_this,ec_uint64 _fl,ec_uint64 _ft);
|
|
|
|
/*Returns the number of bits "used" by the encoded symbols so far.
|
|
The actual number of bits may be larger, due to rounding to whole bytes, or
|
|
smaller, due to trailing zeros that can be stripped, so this is not an
|
|
estimate of the true packet size.
|
|
This same number can be computed by the decoder, and is suitable for making
|
|
coding decisions.
|
|
_b: The number of extra bits of precision to include.
|
|
At most 16 will be accurate.
|
|
Return: The number of bits scaled by 2**_b.
|
|
This will always be slightly larger than the exact value (e.g., all
|
|
rounding error is in the positive direction).*/
|
|
long ec_enc_tell(ec_enc *_this,int _b);
|
|
|
|
/*Indicates that there are no more symbols to encode.
|
|
All reamining output bytes are flushed to the output buffer.
|
|
ec_enc_init() must be called before the encoder can be used again.*/
|
|
void ec_enc_done(ec_enc *_this);
|
|
|
|
#endif
|